Development Of Digital Thermal Conductivity Measurement System

Thermal conductivity measurement of insulation materialsis an important basic experiment in the course of the hot physics teaching in colleges and universities and is a very important practical project. There are two kinds of experimental measurement methods of thethermal conductivity, steady-state methods and transient-state methods according to the different ideas. The steady-state methods have the high accuracy and repeatability, but there are inherent shortcomings of measuring time and equipment complexity.The transient-state methods can obtain the thermal conductivity of the material quickly with enough measurement accuracy.At present, the transient-state methodsare the main application of the test method,and the methods used in universities are mostly the transient-state methods.However, the measuring instruments currently sold in the market are designed foridentification of material parameters. These devices are often expensive and complex to operate, so not used for teaching usually.In the above context,a digital thermal conductivity measurement system for teaching was developedmeeting the requirements of the experimental teaching in the instrument and equipment. The general measurement scheme is designed after analyzed the principle of thermal pulse measurement. With the production design idea of low cost and easy to process, the STM32 works as the control unit, T-type thermocouple is used to measure the temperature of specimen, the control and monitoring circuit is designed to measure the heating voltage and current of heater, display and print circuit to achieve human-computer interaction and data output.We designedsoftware foreasyto operation. The software of the system is divided into two parts, one of is the instrument control program and another is the upper computer program which is used to calculate the test results.The measurement procedure is controlled by the program, without human interference, and the operation of the instrument is simple and quick.The temperature, voltage and current measurement channelsof the instrument are tested and calibrated and the design function of the instrument is verified.The test results show that the design of the instrument is stable and reliable, can beused as a teaching instrument.And now, the delivery of small quantities of products has been completed.Finally, draw the relevant conclusions based on the paper work.